1. Field
The disclosed technology relates to a display device and a driving method thereof, and more particularly, to an organic light emitting diode (OLED) display, to which current consumption reduction technology is applied and a driving method thereof.
2. Description of the Related Technology
A display device has a display area with a plurality of pixels on a substrate in a matrix and has scan lines and data lines connected to each pixel to selectively apply data signals to the pixels, so as to display images. Display devices may, for example, be either a passive matrix light emitting display device or an active matrix light emitting display device depending on the method of driving the pixels. Many display devices are active matrix light emitting display devices in which unit pixels have high resolution, contrast, and operation speed.
Such display devices are used in personal computers, mobile phones, portable information terminals such as PDAs, etc., or in various other information devices. Common types of display technologies include, for example, a liquid crystal display (LCD), an organic light emitting diode (OLED) display, and a plasma panel (PDP). Recently, various light emitting display devices with low weight and volume, as compared to the cathode ray tubes, have been developed. In particular, OLED displays having high luminance efficiency, preferable luminance and viewing angles, and quick response speed are attracting attention.
In the OLED displays, a control method of automatically controlling current (Automatic Current Limit, hereinafter, referred to as ‘ACL’) to lower luminance on the display when the entire screen is lighted at high luminance by video signals in one frame, is used to reduce power consumption. The aforementioned ACL method includes summing all data values for a frame of data on an organic light emitting display panel to determine an average luminance value of the organic light emitting display panel, adjusting a light emission period depending on the luminance value, or changing the image data to control driving current. However, it is hard to apply the aforementioned ACL method because the data to be summed is different from the data for the data rendering technology which has been variously developed for display devices, or optical characteristics of image quality displayed after data rendering may not be guaranteed. Therefore, it is necessary to develop an improved ACL method to be integrated with the data rendering technology and applicable.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.